A variety of expandable intraluminal medical devices have been developed over recent years. For example, stents are routinely used in several body lumens as a means for providing support to ailing vessels, such as coronary and non-coronary vessels. Occlusion devices are used to substantially block fluid flow through a body vessel, and prosthetic valves are used to regulate fluid flow through a body vessel. Both prosthetic heart valves and venous valves have been the subject of significant development efforts in recent years.
Expandable intraluminal medical devices are typically delivered to a point of treatment using a delivery system designed for percutaneous techniques. In a conventional procedure, a caregiver navigates the delivery system through one or more body vessels until the expandable intraluminal medical device, which is typically contained in a distal tip of the delivery system, is positioned at or near the desired point of treatment. Next, the caregiver deploys the expandable intraluminal medical device from the delivery system, either by removing a constraining force for self-expandable devices or by providing an expansive force for balloon-expandable devices. Once deployment is complete, the delivery system is removed from the body vessel, leaving the intraluminal medical device in an expanded configuration at the point of treatment. This delivery and deployment technique is largely conventional and is used for most types of expandable intraluminal medical devices, including stents, occluders, valves, and other types of devices.
During delivery, expandable intraluminal medical devices are maintained in a compressed or reduced-diameter configuration within the delivery system to ensure navigability of the delivery system through the body vessel. The navigability of the delivery system is directly related to its overall outer diameter. A relatively large diameter limits the ability of a delivery system to be navigated past curves, angles, side branch openings and other impediments, and also limits the ability of a delivery system to enter and/or be navigated through small diameter vessels.
Because the delivery system must carry the intraluminal medical device to the point of treatment in the body vessel, efforts to minimize the outer diameter of delivery systems are necessarily confined by the ability of the intraluminal medical device to be compressed. The material, construction, and configuration of the medical device can limit its ability to be compressed, which, in turn, limits the useable outer diameter of the delivery system that will ultimately be used with the device.
Some intraluminal medical devices, including some prosthetic valves and occluders, include graft and/or valve members that add to the bulk of the support frame included in the device, compounding the difficulty associated with increasing the compressibility of the device. Intraluminal filters have presented a particular challenge in this regard as conventional approaches to enhancing the filtering function have tended to increase the overall bulk of these devices in an effort to increase the extent of the interaction between the filter and the fluid flowing through it. A need continues, therefore, for improved low profile medical devices in general and, in particular, for improved intraluminal filter devices.